Devices for producing spools/shuttle spools for shuttles are already known. In these, the emerging yarn part or yarn end has been secured in a manner in which there has been no clear definition of the position of the yarn end. The yarn end has been secured manually against further turns and/or the yarn pirn has been secured with tape or some similar basic fastening means. For producing spools it is also known to apply and rotate a pirn in a spooling machine which comprises a yarn guide which can be activated in the longitudinal direction of the pirn. Yarn from a yarn magazine is fed onto the pirn via the yarn guide. When the full amount of yarn has been applied to the pirn, the yarn end is cut off and secured in the manner stated above.
In connection with weaving machines, a trend has now emerged for the weaving process to be carried out with as few manpower resources and interventions as possible, which requires, among other things, that the spool exchange in the shuttles be carried out automatically. This means, for example, that the tying together, welding together or equivalent joining of the yarn ends from the empty spool and the new spool would be carried out by mechanical means. It is already known to make arrangements for automatic spool exchange and to utilize, for example, tying and welding apparatuses (ultrasonic welding apparatuses) for joining together the yarn ends in question.
Thus, there is a need for better identification of the yarn ends when handling spools in conjunction with spool production and weaving. The present invention solves this problem, among others, and proposes the use of a yarn-end trapper which is placed on the pirn before the yarn application in the spooling machine. By means of, for example, color markings on or of each yarn trapper, clear identification of the yarn quality, thickness, color etc. can be given.
There is also a need, in the handling of shuttle spools, to allocate the yarn ends clear spatial positions. The invention solves this problem too.
There is a need to be able to rationalize spool manufacture as such in conjunction with the production in a spooling machine. The invention solves this problem.
The use of shuttle spools in the weaving process in weaving machines also in itself presupposes that the shuttle and spool functions can be made more efficient. The invention solves this problem by including a yarn trapper, with the possibility of identification as regards quality, thickness etc., which cooperates in the automated procedure for spool exchange. The yarn trapper allows to control the position of the yarn end, for example in automatic tying and welding functions which are used for joining together the yarn ends on new spools which have been wholly or partly unreeled.
In shuttle spool manufacture it is essential for a clear fastening function to be established and made available for fastening the yarn end. The invention solves this problem too. The fastening according to the invention makes it possible to effectively prevent entangling of yarn when the yarn is being fed onto and from the spool in conjunction with spool manufacture, shuttle spool handling and yarn removal when weaving.
The problem associated with manual taping of the yarn end and with sticky tape residues on the pirn and the weft yarn is also eliminated.
It is also important that the yarn end be fastened and cut off automatically in connection with production in the spooling machine. In this context it is important that there should be no loose final turns on the completed shuttle spool. The invention also solves these problems. In one embodiment the yarn spool can be arranged rotatably on the pirn end, among other reasons in order to eliminate the risks of loose yarn turns occurring.
The manufacture of a yarn trapper clearly functioning on the pirn will also be possible. The invention proposes, in a preferred embodiment, that the yarn trapper be produced in a single piece made of elastic material (for example plastic or aluminium). In one embodiment, it is possible to establish mechanical fastening in an efficient manner. The invention solves this problem. Yarns or threads of a thickness of 0.1 mm or coarser can be fastened in an effective manner. The problem with an improved control of the pirn during the yarn application in the spooling machine is also eliminated by the invention.
In weaving machines it is also important to be able to retain maximum weaving widths despite the introduction of the new facilities.
The characterizing feature of the present method for producing a spool for a shuttle in a weaving machine is, among other things, that before or in conjunction with the positioning of the pirn in the rotational arrangement, for example a spooling machine, a yarn-trapping device is preferably arranged at one end of the pirn, after which the yarn is wound on in order to form the spool. After the winding-on of the yarn has been completed, the emerging part of the yarn is brought into cooperation with the yarn-trapping device for the purpose of fixing the emerging yarn part to the trapper, to facilitate the continued handling of the spool. In conjunction with the fixing, the yarn part is cut off, preferably immediately after the fixing position on the yarn-trapping device.
In a further preferred embodiment it is possible to impart to the yarn-trapping device a rotational movement relative to the pirn in order to create a certain retightening of the final turns of the yarn spool, so that these assume "non-loose" positions or states. The yarn is fastened in the spooling machine or equivalent preferably automatically, so that the end result is a spool with yarn-trapping device which fixes the yarn/the yarn end preferably by mechanical means and at the same time holds the yarn turns taut so that there are no loose yarn turns. The rotation of the yarn-trapping device relative to the pirn can also take place automatically.
In one embodiment the emerging yarn part is laid crosswise on the yarn-trapping device in grooves arranged therein. The groove walls are mutually inclined so that an upwardly/outwardly widening gap is formed. The fastening is in this case carried out in such a way that the yarn is clamped securely and held mechanically against the walls of the groove.
The principal feature of the present invention spool intended for a shuttle and having a yarn-trapping device is that the latter is designed such that it can be applied, preferably at a first end, on a pirn included in the spool, and that the yarn-trapping device, in its position when applied on the pirn, is designed to receive the emerging yarn part when the full amount of yarn has been wound onto the pirn and to fasten this part so that "non-loose" final turns occur on the spool.
In a preferred embodiment, the yarn-trapping device is mounted rotatably on the pirn. The yarn-trapping device is in this way arranged to execute a rotational movement relative to the pirn, which is exploited in order to retighten any loose final turns of the yarn on the spool.
The yarn-trapping device can comprise grooves which are preferably arranged at right angles to each other. A first yarn section can in this case be applied in the first groove, and a second yarn section can be arranged in the second groove, at the same time as a third yarn section connecting the first and second yarn sections runs around a first bearing part extending axially on the yarn-trapping device. The yarn sections cross each other in this way, and the upper (the second) yarn section is pressed down against the first yarn section, which reinforces the fastening function. The first yarn section can be applied in the first groove by means of a gripping member. With this gripping member, the third yarn section can be applied around the axially extending first bearing part, at the same time as the spool and the trapper are rotated about a common longitudinal axis, after which the second yarn section can be applied, likewise with the aid of the gripping member, in the second groove and can be pressed down against the first yarn section, as above.
In one embodiment the yarn-trapping device also comprises an end surface which is arranged on the axially extending second bearing part and which forms a stop surface for the spool turns at the first end of the pirn, as a result of which a well-defined stop is obtained for the yarn on the pirn. The first bearing part and/or the part of the yarn-trapping device having the grooves, or both parts together, can exhibit markings which are associated with the quality, thickness, color etc. of the yarn. Different yarn trappers can also be designed with different colors and shades of the yarn trapper material in order to provide the distinction. The yarn trapper is preferably made of elastic material which can consist of plastic, aluminium, etc.
In one embodiment the yarn-trapping device also entails that the first axially extending part will have bearing members for the rotation in the spooling machine. The grooves on the part exhibiting the grooves merge into widened recesses in order to facilitate the introduction and removal of the yarn in the respective groove.
The method for establishing spool exchange in or on a weaving machine, in which the spool with the yarn-trapping device is used, is principally characterized in that a signal or initiation for the spool exchange is extracted from the weaving machine, its program-controlling unit and/or the shuttle system. Before, during or after the removal of the first spool/pirn from the shuttle member, the emerging yarn part of the first spool/pirn is brought into cooperation with trapping members for yarn parts. A new or second spool with yarn-trapping device is applied in the shuttle member, and gripping members are brought into cooperation with the yarn-trapping device on the new or second spool. The gripping and shuttle members have reciprocal movements, during which the yarn-trapping device is removed from the pirn, and yarn turns are drawn off from the new or second spool. During or after the reciprocal movements, the yarn part drawn off from the new or second spool is brought into cooperation with the trapping members for yarn parts for the purpose of joining the first and second yarn parts by means of known apparatuses, for tying together, welding together etc. the yarn ends.
In one embodiment a spool magazine is arranged on the weaving machine, from which the new or second spool is collected or chosen from a number of spools. The collection and the transfer to the shuttle can be carried out automatically (also in a known manner). The spool stock can be raised and lowered relative to the weave in the weaving machine for the purpose of saving space in the machine and of maintaining maximum/optimal weave widths despite the introduction of the automated tying or welding function.
By means of the present invention, considerable advantages are obtained in terms of efficiency in shuttle spool production and shuttle spool handling in weaving machines. The spool production can be rationalized and made considerably less expensive. The present invention increases the efficiency of the function for joining (tying, welding, gluing, etc.) the yarn ends together. No restrictions need be made on the space in the weaving machine for the weave. The manpower needed for operating the weaving machines can be reduced considerably, and there are fewer interruptions in the running of the machines.